Anti-friction buffer



Dec. 29, 1964 G. J. REID ANTI-FRICTION BUFFER Filed April 30, 1963 INVENTOR.

GORDON J. REID United States Patent i 3,163,419 ANTi-FRECTEON BUFFER Gordon .l. Reid, Johnson island, Swartz Bay Road, Sidney, ritish Columbia, Canada Filed Apr. 3 3, i963, Ser. No. 276,969 13 Claims. (Cl. 267l) This invention relates to an anti-friction buffer, particularly for boats, but which may be used for other purposes and which uses the castered wheel principle as its fiictionless component.

It is generally known that during the operation of docking a boat and after the docking thereof, the relative movement of the boat against the dock quite often causes damage to the boat hull. Frictionless bulfers of the caster type will provide continuous rolling friction between the dock and the boat during movement of the boat in any direction substantially parallel with the dock, thus eliminating the rubbing action that would undoubtedly occur with a friction type buffer. Some attempts have been made to produce boat buffers of the caster wheel type. However, these have not been very successful due to the fact that a large thrust against the wheel produces a turning moment which damages bearings and. invariably results in the jamming of the castered wheel about its swivel axis.

The present invention seeks to overcome these drawbacks by providing a buffer of the caster-ed wheel type which will not only absorb the impact of a docking boat but will greatly reduce or eliminate the turning moment created by the thrust upon the castered wheel, thus allowing the wheel to caster freely at all times.

The present invention consists essentially of an antifriction buffer for use between relatively moving elements comprising a mounting base adapted to be mounted on one of the said elements, a spindle rotatably and longitudinally slidably mounted on the said base, resilient means on the base normally urging the spindle to an outer position thereon, a roller carried at the outer end of the spindle with its axis offset in relation to the spindle axis, bearing means carried by the spindle radially outwardly from its axis at least as far as and on the same side of the spindle axis as the roller axis, said bearing means being adapted to engage said one element when a thrust is applied to the periphery of the roller by the other of the said elements, to take the resultant thrust, while allowing the roller and spindle to function as a caster.

An example of thisinvention is illustrated in the accompanying drawings, in which:

FIGURE 1 is an end view of the buffer; and

FIGURE 2 is a side elevation, partially in section, of the buffer.

Refen'ing to the drawings, It) generally represents a mounting base adapted to be mounted on a boat or dock and, in this example, it is mounted on a dock 1 2. The mounting base in this example comprises a substantially flat bearing plate 13 having an outer surface 15 and an inner surface 16, lying substantially flush against the side of the dock, the upper edge 17 of the bearing plate projecting some distance above the top 19 of the dock,

and a second plate 20 lying substantially horizontal to and on the top of the dock 19, being rigidly secured pref erably by Welding to the bearing plate 13. The mounting base is secured to the dock by means of lag screws or bolts 22. It will be understood that the dock may be recessed to receive mounting base it A tubular support shaft 24 of circular crosssection is mounted on the inner end of the second plate 29 such that its axis is perpendicular to the bearing plate 13, one

end 26 of which is open and the other end 28 of which is closed by a cap 39 which is preferably welded to the 3,153,4ld Patented Dec. 29, 1964 ICC support shaft, Cap 30 of support shaft 24 is welded to the second plate 20 so that said shaft is disposed slightly above said second plate and substantially normal to it. A spindle 33 having a bore 35 in the inner end 36 thereof, said bore being slightly larger in diameter than the outer diameter of support shaft 24, is mounted on said support shaft and slidably extends through an aligned aperture 38 in the bearing plate 13. It will thus be seen that the spindle is free to rotate on and is axially slidably relative to the support shaft, being laterally supported by both said support shaft and the apertured plate 13. A chamber 39 formed by the tubular support shaft and the spindle bore contains a spring 4% under compression. It will thus be seen by referring to FIGURE 2 that the spindle is continually urged outwardly and away from the support shaft. In this example, the outward movement of the spindle is limited by stops 42 secured to the spindle and adapted to engage the inner surface 16 of the bearing plate 13.

The spindle 33 has a yoke 44 mounted on the outer end 46 thereof. The yoke 44 comprises a pair of outwardly extending plates 48 mounted rigidly parallel to each other on a common yoke base 50. The yoke base 50 is rigidly secured, preferably by welding, to the outer end 46 of spindle 33 perpendicularly to the axis of the spindle, one side 52 of the yoke extending radially some distance outwardly of the spindle. A roller 54, which in this example is a pneumatic tire wheel, is mounted for rotation within the yoke on an axle 56 secured to the yoke by nuts 58. The axle 56 of the roller is offset radially from the axis of the spindle by a caster distance indicated as A shown upon FIGURE 2, thereby forming a caster.

Suitable bearing means, preferably of the roller or ball bearing type, is mounted on the yoke base 50 between the said base and the outer surface 15 of the bearing plate 13 and so disposed thereon that it will engage the said outer face 15 upon the roller 54 and spindle 33 moving inwardly. In this example, the said bearing means comprises a pair of rubber tired dollies 60 mounted for rotation in brackets 62, said brackets mounted on and up standing outwardly from the yoke base 50, the axis of each dolly aligned radially to the spindle33. The dollies 60 are disposed on the yoke base 50 such that their effective centre of support lies outwardly of said spindle 33 in the same direction as the caster distance. A and not less than such said distance, and on the same side ofthe spindle axis as the axle 56 of the roller 54. 'The foregoing is clearly illustrated in FIGURE .1, in which the effective centre of support of the dollies 60 is shown as a dotted line 62, the distance from the said dottedline 62 to the said spindle axis being indicated as B.

In normal use, the'bufler willoverhang the side of the dock in such a position that a docking boat will come into contact with rubber tired wheel 54. The wheel will then caster in any direction, dependent upon the relative movement of the boat m ne dock. The thrust imposed by the boat against the roller will urge both roller and spindle 33 inwardly, thereby compressing the spring 49. If the thrust is not too great, the spring will only slightly compress. However, if the thrust is great, the spring will compress untildollies 6t) engage the outer surface 15 of the bearing plate 13, thereby transferring most of the force of the said thrust to the bearing plate, dollies. 60 enabling roller 54 to caster even under conditions of extreme loading.

Referring to FIGURE 2, it'will be seen that a thrust designated as T will ordinarily produce a turning moment M in the direction shown by the curved arrow L about the point of contact between spindle 33 and bearing plate 13 at aperture 38. If the device did not ha e a the dolly support, it will readily be seen that the consequent friction between the plate and the spindle and between the spindle and support shaft 24 might prevent the device from .castering. This might to some extent be overcome by the use of special bearings, however, where great thrusts are encountered, even specially built bearings would tend to jam. With'the addition of the dollies which transmit the greater part of the thrust vertically against the bearing plate 13, the turning moment M is thereby eliminated, all of the thrust being taken vertically by the dollies and the spring 46, thereby allowing the spindle to rotate freelywith very little, if any, side friction against either the apertured plate 13 or the support shaft 24. The present buffer due to the rubber tired wheel and rubber tired dollies not only serves to provide a rolling friction between the docking boat and the dock, but provides a resilient buffer to absorb the shock of impact between the dock and boat.

It will be appreciated that the bow of a-docking boat might strike the yoke plates 48 before engaging the roller 54. A pair of angled braces 64 are therefore secured, preferably by welding between the base 50 and said yoke plates 48, said braces serving as guides to direct the bow of the boat into engagement with the roller 54.

What I claim as my invention is:

1. An anti-friction buffer for use between relatively moving elements comprising a mounting base adapted to be mounted on one of the said elements and having a substantially horizontal support shaft projecting outwardly therefrom, a hollow spindle member rotatably and slidably mounted on said support shaft, resilient means at the support shaft normally urging the spindle member to an outer position thereon, rolling bearing means carried at the outer end of the spindle member with its axis offset in relation to the spindle member axis, rolling bearing means carried by the spindle member radially outwardly from its axis at least as far as and on .the same side of the spindle member axis as the roller axis, said rolling bearing means being adapted to engage said one element when a thrust is applied to the periphery of the roller by the other of the said elements to take the resultantthrust, while allowing the roller and spindle member to function as a caster.

2. An anti-friction buffer as claimed in claim 1 in which the resilient means comprises a compression spring mounted between the support shaft and spindle member and pressing outwardly against the spindle member so that the Spindle .member is normally urged to an outer position.

3. An anti-friction buffer for use between relatively moving elements comprising a mounting base adapted to' be mounted on one of the said elements and having a substantially hon'zontalsupport shaft projecting outwardly therefrom, a hollow spindle rotatably and slidably mounted on said support shaft, resilient means .at the support shaft normally urging the spindle to an outer position thereon, a yoke having a, yoke base mounted on the outerend of the spindle, said yoke'base being perpendicular to the axis of the spindle and projecting radially outwardly therefrom, a roller mounted for rotation Within the yoke with its aids offset in relation to the axis of the spindle, rolling bearing means carried by the yoke base radially outwardly from thespindle axis at least as far and on the same side of the "spindle axis as the roller axis, said rolling bearing means being adapted to engage said one element when a thrust is applied to theperiphcry of the roller-by the other of the said elements, to take the resultant thrust, while allowing the roller and spindle to function as a caster.

'4. An anti-friction buffer as claimed in claim 3 including a bearing plate, having a substantially smooth .outer face, fixedly secured to the mounting base perpendicular to the axis of the spindle and disposed outwardly of the support shaft so as to permit the rolling bearing 4 means to engage said outer face when a thrust is applied to the roller.

5. An anti-friction buffer as claimed in claim 4 in which the bearing plate slidably and-rotatably embraces the spindle thereby serving as a lateral support for said spindle.

6. An anti-friction buffer as claimed in claim 4 including stop means projecting laterally from the spindle, said stop means being adapted to engage the inner face of the bearing plate to limit the outward movement of the spindle.

7. An anti-friction buffer as claimed in :claim 3 in which the roller is rubber tired.

8. An anti-friction buffer for use between relatively moving elements comprising a mounting base adapted to be mounted on one of the said elements and having an outwardly-projecting substantially horizontal cylindrical support shaft with a bore, a bearing plate having a relatively smooth outer surface fixedly connected to the mounting base perpendicular to the axis of the support shaft and extending outwardly therefrom, said bearing plate having a circular aperture therein, a hollow spindle rotatably and slidably mounted on the support shaft, said spindle projecting through the aperture in the bearing plate and being slidably and rotatably supported by said plate, a compression spring mounted within the bore of the support shaft, said spring urging the spindle to an outer position, a yoke mounted on the outer end of the spindle, said yoke having a yoke .base perpendicular to the axis of the spindle and projecting radially outwardly therefrom, a rubber tired roller mounted for rotation relative to the axis of the spindle, bearing means carried by the yoke base radially outwardly from the spindle axis at least as far and on the same side of the spindle axis as the roller axis, said bearing means being adapted to engage the outer face of the bearing plate when a thrust is applied to the periphery of the roller by the other of the said elements, to take the said resultant thrust while allowing the roller and spindle to function as a caster.

9. An anti-friction buffer as claimed in claim 8 in which the bearing means comprises at least one rolling bearing.

10. An anti-friction buffer as claimed in claim 8 including stop means projecting laterally from the spindle, said stop means being adapted to engage the inner face of the bearing plate to limit the outward movement of the spindle.

11. An anti-friction buffer as claimed in claim 9 in which the rolling bearing is a rubber tired wheel.

12. An anti-friction bulfer as claimed in claim 9 including a pair of guides secured to the base to guide the other of said elements into engagement with the periphery of the roller.

13. An' anti-friction buffer for use between relatively moving elements, comprising a mounting base adapted to be mounted on one of the said elements, a spindle rotatably and longitudinally slidably mounted on the said base, resilient means on :the base normally urging the spindle to an outer position thereon, a roller carried at the outer end' of the spindle with its axis offset in relation to the spindle axis, at least one rolling bearing means carried by the spindle radially outwardly from its axis at least as far and on'the same side of the spindle axis as the roller axis, said bearing means being adapted to engage said one element when a thrust is applied to the periphery of the roller by the other of the said elements, to take the resultant thrust, while allowing the roller and spindle to function as a caster.

References. Cited in the file of this patent UNITED STATES PATENTS 

1. AN ANTI-FRICTION BUFFER FOR USE BETWEEN RELATIVELY MOVING ELEMENTS COMPRISING A MOUNTING BASE ADAPTED TO BE MOUNTED ON ONE OF THE SAID ELEMENTS AND HAVING A SUBSTANTIALLY HORIZONTAL SUPPORT SHAFT PROJECTING OUTWARDLY THEREFROM, A HOLLOW SPINDLE MEMBER ROTATABLY AND SLIDABLY MOUNTED ON SAID SUPPORT SHAFT, RESILIENT MEANS AT THE SUPPORT SHAFT NORMALLY URGING THE SPINDLE MEMBER TO AN OUTER POSITION THEREON, ROLLING BEARING MEANS CARRIED AT THE OUTER END OF THE SPINDLE MEMBER WITH ITS AXIS OFFSET IN RELATION TO THE SPINDLE MEMBER AXIS, ROLLING BEARING 